A dairy-based, protein-rich breakfast enhances satiety and cognitive concentration before lunch in overweight to obese young females: A randomized controlled crossover study.

The purpose of this study was to investigate if consumption of a high-protein, low-carbohydrate breakfast (PRO) leads to a lower subsequent ad libitum energy intake at lunch and the rest of the day compared with ingestion of an isocaloric low-protein, high-carbohydrate breakfast (CHO) or no breakfast (CON). The study was designed as a randomized controlled 3-period crossover study. Thirty young (18-30 yr) females with overweight to obesity (body mass index >25 kg/m2) in random order completed 3 separate experimental days where they consumed either a PRO, CHO, or CON breakfast test meal followed by an ad libitum lunch meal 3 h after breakfast. Participants were allocated to a sequence group by their inclusion number. The PRO and CHO breakfasts were matched in dietary fiber and fat content. Energy intake at lunch was calculated and dietary records were obtained for the rest of the day to calculate the total daily energy intake and macronutrient intake. Ratings of appetite sensations between meals and palatability of the test meals were assessed using visual analog scale sheets in intervals ranging from 10 to 30 min. In addition, blood samples were obtained at multiple time points separated by 10 to 60 min intervals between breakfast and lunch and were analyzed for appetite-regulating gut hormones, insulin, and glucose. Finally, performance in a cognitive concentration test was tested 150 min after breakfast. Compared with CHO and CON, the area under the curves for satiety, fullness, and satisfaction in the 3 h after breakfast were significantly higher after PRO, whereas the areas under the curve for hunger, desire to eat, and prospective eating were significantly lower after PRO. The appetite-regulating gut hormones cholecystokinin, glucagon-like peptide-1, and ghrelin in the hours after breakfast, energy intake during the ad libitum lunch meal, and the total daily energy intake did not differ significantly between PRO, CHO, and CON. However, the cognitive concentration test score was 3.5 percentage points higher for PRO, but not CHO, versus CON. A dairy-based high-protein, low-carbohydrate breakfast increased satiety sensation in the hours after breakfast but did not reduce total daily energy intake compared with an isocaloric low-protein, high-carbohydrate breakfast or omitting breakfast. However, performance in a cognitive concentration test before lunch was enhanced after the high-protein, low-carbohydrate breakfast, but not the low-protein, high-carbohydrate breakfast, compared with omitting breakfast.

Long-term complications after infection with SARS-CoV-1, influenza and MERS-CoV - Lessons to learn in long COVID?

The COVID-19 pandemic has affected millions of people worldwide, and while the mortality rate remains the primary concern, it is becoming increasingly apparent that many COVID-19 survivors experience long-term sequelae, representing a major concern for both themselves and healthcare providers. Comparing long-term sequelae following COVID-19 to those of other respiratory viruses such as influenza, MERS-CoV, and SARS-CoV-1 is an essential step toward understanding the extent and impact of these sequelae. A literature search was carried out using the PubMed. database. Search-terms included "persistent", "long-term", "chronic", and MeSH-terms for SARS-CoV-1, MERS-CoV and Influenza. Only English-language articles were selected. Articles were screened by title/abstract and full-text readings. Key points for comparison were persistent symptoms > 4 weeks, virus type, study design, population size, admission status, methods, and findings. Thirty-one articles were included: 19 on SARS-CoV-1, 10 on influenza, and 2 on MERS-CoV-survivors. Damage to the respiratory system was the main long-term manifestation after the acute phase of infection. Quality of life-related and psychological sequelae were the second and third most widely reported symptoms, respectively. Consistent with long-term sequelae from COVID-19, persisting cardiovascular, neurological, musculoskeletal, gastrointestinal impairments were also reported. In summary, the long-term sequelae following COVID-19 are a significant concern, and while long-term sequelae following influenza, MERS-CoV, and SARS-CoV-1 have also been reported, their prevalence and severity are less clear. It is essential to continue to study and monitor the long-term effects of all respiratory viruses so as to improve our understanding and develop strategies for prevention and treatment.

Calcium electroporation and electrochemotherapy for cancer treatment: Importance of cell membrane composition investigated by lipidomics, calorimetry and in vitro efficacy.

Calcium electroporation is a novel anti-cancer treatment investigated in clinical trials. We explored cell sensitivity to calcium electroporation and electroporation with bleomycin, using viability assays at different time and temperature points, as well as heat calorimetry, lipidomics, and flow cytometry. Three cell lines: HT29 (colon cancer), MDA-MB231 (breast cancer), and HDF-n (normal fibroblasts) were investigated for; (a) cell survival dependent on time of addition of drug relative to electroporation (1.2 kV/cm, 8 pulses, 99 µs, 1 Hz), at different temperatures (37 °C, 27 °C, 17 °C); (b) heat capacity profiles obtained by differential scanning calorimetry without added calcium; (c) lipid composition by mass spectrometry; (d) phosphatidylserine in the plasma membrane outer leaflet using flow cytometry. Temperature as well as time of drug administration affected treatment efficacy in HT29 and HDF-n cells, but not MDA-MB231 cells. Interestingly the HT29 cell line displayed a higher phase transition temperature (approximately 20 °C) versus 14 °C (HDF-n) and 15 °C (MDA-MB231). Furthermore the HT29 cell membranes had a higher ratio of ethers to esters, and a higher expression of phosphatidylserine in the outer leaflet. In conclusion, lipid composition and heat capacity of the membrane might influence permeabilisation of cells and thereby the effect of calcium electroporation and electrochemotherapy.

Identification and Characterization of a Nationwide Danish Adult Common Variable Immunodeficiency Cohort.

In this study, we identified all adults living in Denmark diagnosed with common variable immunodeficiency (CVID) and characterized them according to clinical presentation and EUROclass classification. Using a retrospective, cross-sectional design, possible CVID patients were identified in the Danish National Patient Register and Centers in Denmark treating patients with primary immunodeficiencies. The CVID diagnosis was verified by review of medical records. One-hundred-seventy-nine adults with CVID were identified. This corresponds to a prevalence of 1:26,000. The median age at onset of symptoms was 29 years with no sex difference. The median age at diagnosis was 40 years. Males were diagnosed earlier with a peak in the fourth decade of life, whereas females were diagnosed later with a peak in the sixth decade. The median diagnostic delay was seven years. Recurrent sinopulmonary infections were seen in 92.7% of the patients. The prevalence of non-infectious complications was similar to that of previously reported cohorts: bronchiectasis (35.8%), splenomegaly (22.4%), lymphadenopathy (26.3%), granulomatous inflammation (3.9%) and idiopathic thrombocytopenic purpura (14.5%). Non-infectious complications were strongly associated with B cell phenotype, with all having a reduced number of isotype-switched memory B cells. One-hundred-seventy (95%) were treated with immunoglobulin replacement therapy, primarily administered subcutaneously. According to international guidelines, diagnostic evaluation was inadequate in most cases. This study emphasizes the need for improved diagnostic criteria and more awareness of CVID as a differential diagnosis. Diagnosis and management of CVID patients is a challenge requiring specialists with experience in the field of PID.

MicroRNAs in metabolism.

MicroRNAs (miRNAs) have within the past decade emerged as key regulators of metabolic homoeostasis. Major tissues in intermediary metabolism important during development of the metabolic syndrome, such as ß-cells, liver, skeletal and heart muscle as well as adipose tissue, have all been shown to be affected by miRNAs. In the pancreatic ß-cell, a number of miRNAs are important in maintaining the balance between differentiation and proliferation (miR-200 and miR-29 families) and insulin exocytosis in the differentiated state is controlled by miR-7, miR-375 and miR-335. MiR-33a and MiR-33b play crucial roles in cholesterol and lipid metabolism, whereas miR-103 and miR-107 regulates hepatic insulin sensitivity. In muscle tissue, a defined number of miRNAs (miR-1, miR-133, miR-206) control myofibre type switch and induce myogenic differentiation programmes. Similarly, in adipose tissue, a defined number of miRNAs control white to brown adipocyte conversion or differentiation (miR-365, miR-133, miR-455). The discovery of circulating miRNAs in exosomes emphasizes their importance as both endocrine signalling molecules and potentially disease markers. Their dysregulation in metabolic diseases, such as obesity, type 2 diabetes and atherosclerosis stresses their potential as therapeutic targets. This review emphasizes current ideas and controversies within miRNA research in metabolism.

Syntaxin-1a is a direct target of miR-29a in insulin-producing ß-cells.

Downregulation of proteins involved in the -exocytotic machinery has been implicated in the impairment of normal ß-cell function in response to high glucose levels. Syntaxin-1a -(Stx-1a) is one of two t-SNAREs involved in insulin exocytosis and decreased expression of Stx-1a protein impairs glucose-stimulated insulin secretion (GSIS) in isolated rat pancreatic islets. In diabetic patients Stx-1a protein levels are reduced, but the mechanism of this suppression is unknown.MicroRNAs are small noncoding RNAs, which are important regulators of gene-expression at the post transcriptional level, partially binding to the 3'UTRs of their target gene transcripts either mediating transcript degradation or inhibiting translation. We have recently shown that miR-29a is upregulated in response to elevated glucose levels in ß-cells and is involved in mediating the negative effect of high glucose levels on GSIS. Stx-1a has a predicted target site of miR-29a present in its 3' untranslated region. The objective of this study was to evaluate whether miR-29a targets Stx-1a directly to decrease mRNA and/or protein levels in response to glucose. Stx-1a mRNA and protein levels decreased in ß-cells treated with increased glucose levels. Overexpression of miR-29a decreased Stx-1a mRNA and protein levels. Furthermore, miR-29a decreases the response of a luciferase reporter construct containing the predicted target site normally present in the Stx-1a gene. When 2 nucleotides are mutated in this target site, responsiveness to miR-29a disappears, confirming miR-29a binding to this sequence. Collectively, these data implicate miR-29a as a mediator of glucose-induced downregulation of Stx-1a in ß-cells.

The frequent UCP2 -866G>A polymorphism protects against insulin resistance and is associated with obesity: a study of obesity and related metabolic traits among 17 636 Danes.

CONTEXT: Uncoupling protein 2 (UCP2) is involved in regulating ATP synthesis, generation of reactive oxygen species and glucose-stimulated insulin secretion in ß-cells. Polymorphisms in UCP2 may be associated with obesity and type 2 diabetes mellitus. OBJECTIVE: To determine the influence of a functional UCP2 promoter polymorphism (-866G>A, rs659366) on obesity, type 2 diabetes and intermediary metabolic traits. Furthermore, to include these and previously published data in a meta-analysis of this variant with respect to its impact on obesity and type 2 diabetes. DESIGN: We genotyped UCP2 rs659366 in a total of 17 636 Danish individuals and established case-control studies of obese and non-obese subjects and of type 2 diabetic and glucose-tolerant subjects. Meta-analyses were made in own data set and in publicly available data sets. Quantitative traits relevant for obesity and type 2 diabetes were analysed within separate study populations. RESULTS: We found no consistent associations between the UCP2 -866G-allele and obesity or type 2 diabetes. Yet, a meta-analysis of data from 12 984 subjects showed an association with obesity (GA vs GG odds ratio (OR) (95% confidence interval (CI)): 0.894(0.826-0.968) P=0.00562, and AA vs GG OR(95% CI): 0.892(0.800-0.996), P=0.0415. Moreover, a meta-analysis for type 2 diabetes of 15 107 individuals showed no association. The -866G-allele was associated with elevated fasting serum insulin levels (P=0.002) and HOMA insulin resistance index (P=0.0007). Insulin sensitivity measured during intravenous glucose tolerance test in young Caucasian subjects (n=377) was decreased in carriers of the GG genotype (P=0.05). CONCLUSIONS: The UCP2 -866G-allele is associated with decreased insulin sensitivity in Danish subjects and is associated with obesity in a combined meta-analysis.

Basal and T3-induced ROS production in lymphocyte mitochondria is increased in type 2 diabetic patients.

Mitochondrial function, including production of reactive oxygen species (ROS), is important in the pathogenesis of diabetes and its complications. Thyroid hormones are major regulator of these processes. Hence, the aim of this study was to examine the thyroid hormone regulation of ROS production in human lymphocytes in patients with diabetes mellitus type 2 (T2DM). Lymphocytes from 10 controls and 10 persons with T2DM were examined. Mitochondrial membrane potential (MMP) was examined by flow cytometry after staining with MitoTracker Green (MTG). Similarly ROS was measured following staining with carboxy-H2DCFDA. MMP was increased in T2DM patients and T3 stimulation increased MMP in controls [1398 a.u. (979-4094) vs. 2156 a.u. (1611-15189), p=0.04, median and quartiles] as well as in T2DM patients [9167 a.u. (7387-11746) vs. 20274 a.u. (17183-27839 p=0.004, median and quartiles]. Basal ROS concentration was increased in lymphocytes from T2DM and T3 significantly stimulated ROS concentration in controls [3691 a.u. (2584-6396) vs. 5650 a.u. (3001-7802) p=0.013, median and quartiles] and in T2DM patients [19271 a.u. (6288-25282) vs. 23178 a.u. (10004-28857) p=0.013, median and quartiles]. The ratio of ROS production related to MMP was significantly higher in T2DM, unstimulated as well as T3-stimulated in T2DM. Unstimulated and T3 stimulated ROS production and MMP were higher in lymphocytes from diabetic patients. An altered balance between ROS production and MMP, favoring ROS production in T2DM patients, was found suggesting that an increased mitochondrial sensitivity for T3 may be a significant factor responsible for increased ROS activity in diabetic patients.

The glycolipid sulfatide protects insulin-producing cells against cytokine-induced apoptosis, a possible role in diabetes.

AIMS/HYPOTHESIS: Cytokine-induced apoptosis is recognised as a major cause of the decline in ß-cell mass that ultimately leads to type 1 diabetes mellitus. Interleukin-1ß, interferon-γ and tumour necrosis factor-α in conjunction initiate a series of events that lead to ß-cell apoptosis; important among these is NO production. The glycosphingolipid sulfatide is present in ß-cells in the secretory granules in varying amounts and is secreted together with insulin. We now investigate whether sulfatide is able to protect insulin-producing cells against the pro-apoptotic effect of interleukin-1ß, interferon-γ and tumour necrosis factor-α. METHODS: INS-1E cells and genuine rat islets were incubated for 24 h exposed to interleukin-1ß, interferon-γ and tumour necrosis factor-α with or without sulfatide. The production of NO was monitored and the number of apoptotic cells was determined using terminal deoxynucleotidyl transferase-mediated dUTP Nick-End labelling and caspase-3/7 activity assays. In addition, the amount of iNOS mRNA was determined using real-time quantitative polymerase chain reaction. RESULTS: Cytokine-induced apoptosis was reduced to 27% of cytokine-treated controls with 30 µmol/L sulfatide treatment (p < 0.01). Likewise, sulfatide in concentrations of 3-30 µmol/L decreased NO production in a dose-dependent manner to 19-40% of cytokine-treated controls (overall p = 0.0007). The level of iNOS mRNA after cytokine exposure was reduced to 55% of cytokine-treated controls with 30 µmol/L of sulfatide. CONCLUSIONS/INTERPRETATION: In the present study, we report the ability of sulfatide to significantly reduce apoptosis, cellular leakage and NO production in insulin-producing cells. Data suggest this is not due to induction of ß-cell rest. Our findings indicate a possible implication for sulfatide in the pathogenesis of diabetes.

LMNA rs4641 and the muscle lamin A and C isoforms in twins--metabolic implications and transcriptional regulation.

CONTEXT: Lamins are essential for nuclear shape and function. Polymorphisms in LMNA may associate with fat and muscle development and aging. OBJECTIVE: Our aim was to determine the influence of LMNA rs4641 on lean body mass (LBM) and fat mass (FM), in vivo metabolism, and expression of LMNA transcripts in human skeletal muscle. DESIGN: We genotyped LMNA rs4641 in 196 Danish twins who were extensively phenotypically characterized. We measured mRNA levels of LMNA transcripts, lamin A and C, in basal and insulin-stimulated skeletal muscle biopsies. RESULTS: The rs4641 T-allele was associated with increased weight and body mass index (P=0.02), including increased FM (P=0.03) and LBM (P=0.004). Impact of rs4641 on FM was seen primarily among elderly twins. The T-allele was associated with elevated fasting plasma insulin levels (P=0.01) and homeostasis model of insulin resistance (P=0.02) in young twins. T-allele carriers did not exhibit consistent changes of first phase insulin secretion, nor did they exhibit significant peripheral or hepatic insulin resistance, and rs4641 did not influence muscle lamin A or C mRNA levels. The lamin A-to-C mRNA ratio was increased with acute insulin stimulation (P<0.0005), and the lamin A and C mRNA levels were diminished in young compared to elderly twins (P<0.001). CONCLUSIONS: The LMNA rs4641 T-allele is associated with increased LBM and FM with more fat relative to muscle in elderly twins, which may impact risk of type 2 diabetes. Increased mRNA levels of lamins with age may counteract muscle wasting, and influence of insulin on lamin A-to-C ratio suggests a role in cytoskeletal muscle protein regulation.

Development of an in vitro assay for the investigation of metabolism-induced drug hepatotoxicity.

In a number of adverse drug reactions leading to hepatotoxicity drug metabolism is thought to be involved by generation of reactive metabolites from nontoxic drugs. In this study, an in vitro assay was developed for measurement of the impact of metabolic activation of compound on the cytotoxicity toward a human hepatic cell line. HepG2 cells were treated for 6 h with compound in the presence or absence of rat liver S9-mix, and the viability was measured using the MTT test. The cytotoxicity of cyclophosphamide was substantially increased by S9-mix in the presence of NADPH. Three NADPH sources were tested: NADPH (1 mmol/L) or NADPH regenerating system with either NADP(+)/glucose 6-phosphate (G6P) or NADP(+)/isocitrate. All three NADPH sources increased the cytotoxicity of cyclophosphamide to a similar extent. Eight test compounds known to cause hepatotoxicity were tested. For these, only the cytotoxicity of diclofenac was increased by S9 enzymes when an NADPH regenerating system was used. The increased toxicity was NADPH dependent. Reactive drug metabolites of diclofenac, formed by NADPH-dependent metabolism, were identified by LC-MS. Furthermore, an increase in toxicity, not related to enzymatic activity but to G6P, was observed for diclofenac and minocycline. Tacrine and amodiaquine displayed decreased toxicity with S9-mix, and carbamazepine, phenytoin, bromfenac and troglitazone were nontoxic at all tested concentrations, with or without S9-mix. The results show that this method, with measurement of the cytotoxicity of a compound in the presence of an extracellular metabolizing system, may be useful in the study of cytotoxicity of drug metabolites.

Interactions between physical activity and variants of the genes encoding uncoupling proteins -2 and -3 in relation to body weight changes during a 10-y follow-up.

OBJECTIVE: To examine interactions between physical activity and possibly functional variants of the genes encoding uncoupling proteins -2 and -3 in relation to body weight change. We hypothesize that physical inactivity acts synergistically with a 45 bp insertion variant in the 3'untranslated region (3'UTR) of the UCP2-gene and with a t-allele of codon -55 in the promoter of the UCP3-gene in relation to subsequent weight change. DESIGN: Population-based longitudinal study of cohorts of juvenile obese and nonobese men, who were identified at the mandatory draft board examination in Copenhagen and adjacent regions at a median age of 19 y in 1943-77 and later examined at general health surveys in 1981-83 and 1991-93. The juvenile obese cohort included 568 men who at the draft board had a BMI > or =31 kg/m2 and the cohort of controls included 717 randomly selected draftees. MEASUREMENTS: Height and weight were measured, and information about physical activity was collected from a self-administered questionnaire. The genotyping of the polymorphisms was performed using RFLP techniques. The main outcome measure was change in BMI during the 10-y follow-up period. Additional outcome measures were obesity, waist circumference and body fat mass index measured at follow-up. RESULTS: Physical activity, the 3'UTR insertion polymorphism and the -55 c/t polymorphism were not consistently associated with changes in BMI, and there were no evidence for interactions between the UCP-variants and physical activity in relation to changes in BMI. No evidence for interaction between the UCP-variants and physical activity was found in relation to the additional obesity measures. CONCLUSION: This study does not support that interactions between physical activity and variants in the UCP2- or UCP3-gene are major determinants of subsequent weight changes in Danish Caucasian men.

Uncoupling proteins: functional characteristics and role in the pathogenesis of obesity and Type II diabetes.

Uncoupling proteins are mitochondrial carrier proteins which are able to dissipate the proton gradient of the inner mitochondrial membrane. This uncoupling process reduces the amount of ATP generated through an oxidation of fuels. The hypothesis that uncoupling proteins (UCPs) are candidate genes for human obesity or Type II (non-insulin-dependent) diabetes mellitus is based on the finding that a chemical uncoupling of the mitochondrial membrane reduces body adiposity, and that lower metabolic rates predict weight gain. It is straightforward to hypothesize that common polymorphisms of UCP1, UCP2 and UCP3 genes lower metabolic rate by a more efficient energy coupling in the mitochondria. Furthermore, genetically engineered mice over expressing different UCP homologues are lean and resistant to diet-induced obesity. The three uncoupling protein homologue genes UCP1, UCP2, and UCP3 have been investigated for polymorphisms and mutations and their impact on Type II diabetes mellitus, obesity, and body weight gain or BMI. The main conclusion is that variation in the UCP1, UCP2 or UCP3 genes is not associated with major alterations of body weight gain. The contribution of UCP genes towards polygenic obesity and Type II diabetes is evaluated and discussed.

The association between the val/ala-55 polymorphism of the uncoupling protein 2 gene and exercise efficiency.

BACKGROUND: Energy expenditure may partly be determined by genetic variations in uncoupling proteins. We have previously found an increased physical activity but a similar 24-h energy expenditure (EE) in subjects with the val/val-55 UCP2 genotype compared to those with the ala/ala genotype which indicates that the val-55 allele is statistically associated with a higher metabolic efficiency. DESIGN: EE during bicycling was determined by indirect calorimetry at three different loads (30, 40 and 60% of VO2max in eight subjects with the val/val-55 genotype (35+/-6 y weight=76.8+/-13.6 kg, VO2max=2.79+/-0.71 l/min) and eight subjects with the ala/ala-55 genotype (37+/-3 y, weight=78.3+/-16.5 kg, VO2max=2.66+/-0.41 l/min). RESULTS: Incremental exercise efficiency across the three different work levels was higher in the val/val (25.3%, c.i. 24.2-26.4%) than in the ala/ala (23.6%, c.i. 22.5-24.7%) genotype P<0.05. Gross exercise efficiency at 40% VO2max was higher in the val/val (15.3+/-0.6%) than in the ala/ala (13.5+/-0.4%) group. CONCLUSION: As the val/ala-55 polymorphism is located in a domain of the protein without any known function, the different exercise efficiency between the two genotypes most likely reflects a linkage disequilibrium with a functionally significant polymorphism in UCP2 or in the neighbouring UCP3 gene. The study suggests that variations in the UCP genes may affect not only basal metabolic rate but also influence energy costs of exercise.

A prevalent polymorphism in the promoter of the UCP3 gene and its relationship to body mass index and long term body weight change in the Danish population.

Variability of the uncoupling protein 3 (UCP3) promoter has been associated with increased body mass index (BMI) and altered lipid profiles. Here we tested the hypothesis that variation of the UCP3 promoter is associated with either juvenile or maturity-onset obesity or body weight change over a 26-yr follow-up among Danish subjects. Mutation screening of approximately 1 kb 5' upstream of the UCP3 gene revealed one previously described -55 C-->T variant. The frequency of the polymorphism was evaluated by restriction fragment length polymorphism analysis in four groups of subjects: 1) a group of 744 obese Danish men who at the draft board examinations had a body mass index (BMI) of at least 31 kg/m(2), 2) a randomly selected control group consisting of 857 draftees, 3) 258 middle-aged subjects, and 4) 409 60-yr-old subjects. The frequency of the T allele was 26.0% (95% confidence interval, 23.8-28.2%) among the obese draftees and 26.9% (24.8-29.0%) in the control group (P = 0.6). The variant was not associated with BMI at a young age or with weight gain after a 26-yr follow-up. The frequency of the T allele was 29.5% (25.6-33.4%) in the middle-aged group and 25.8% (22.8-28.8%) among the 60-yr-old subjects. The polymorphism was not associated with increased BMI or percent body fat in these 2 groups. It is concluded that this variant does not play a major role in the development of common obesity among Danish subjects.

Evaluation of blood-brain barrier passage of a muscarine M1 agonist and a series of analogous tetrahydropyridines measured by in vivo microdialysis.

PURPOSE: To investigate the blood-brain barrier (BBB) passage of the M1 muscarine agonist Lu 25-109 (5-(2-Ethyl-2H-tetrazol-5-yl)-1,2,3,6-tetrahydro-methylpyridine) and potential metabolites using in vivo microdialysis. METHODS: Anesthetized rats were administered an intravenous infusion of one of seven analogs with a Log D7.4 ranging from 0.35 to -2.4. Microdialysis probes were implanted in the brain and the jugular vein. The integrity of the BBB was evaluated using 2-amino-3-(3-hydroxy-5-phenylisoxazol-4-yl)propionic acid (APPA), a compound not expected to penetrate the BBB. The data was corrected for in vitro recovery. RESULTS: Lu 25-109, Lu 24-165 (demethylated Lu 25-109) and Lu 25-077 (N-demethylated Lu 25-109) entered the brain in a 1:1 ratio with the blood. Although Lu 29-081 (hydroxylated Lu 25-109) presented a similar Log D7.4 to Lu 25-109 and Lu 24-164, it entered the brain with a lower brain:blood ratio of 0.5. Lu 32-181 (Lu 25-109 N-oxide), Lu 35-026 (deethylated and oxidized Lu 25-109) and Lu 31-126 (deethylated Lu 25-109) were not detected in the brain samples, indicating no penetration. Infusion of Lu 25-109 resulted in a time perspective of the formation and distribution of the two metabolites Lu 25-077 and Lu 32-181. Although the hydroxylated compound (Lu 29-081) had a Log D74 of -0.6, within the range 0.35 to -0.83 of the compounds penetrating the BBB, it showed a brain: blood ratio of 0.5. Lu 35-026 showed an unusual infusion profile with a tmax of 100-150 min and a subsequent decrease in blood concentration. CONCLUSIONS: Compounds with Log D7.4 above -0.83 penetrated the BBB, whereas compounds below -1.5 did not. Knowledge of Log D7.4 values is not sufficient to evaluate BBB passage because the value does not predict the influence of active transport processes.

Impact of the v/v 55 polymorphism of the uncoupling protein 2 gene on 24-h energy expenditure and substrate oxidation.

OBJECTIVE: The gene that codes for a novel uncoupling protein, UCP2, has been linked to obesity in animal models. Markers encompassing the UCP2 locus have been linked to energy expenditure in humans. We studied the role of a common amino acid substitution, replacing an alanine (A) with a valine (V) at codon 55, of the coding region of the UCP2 gene for 24-h energy expenditure and respiratory quotient (RQ) in healthy subjects METHODS: 24-h energy expenditure and RQ were measured in calorimeters in 60 healthy subjects. The UCP2 polymorphism was determined by restriction fragment length polymorphism-generating polymerase chain reaction. RESULTS: Age, gender and body fat were not different between groups, the number of subjects in each groups was A/A: 35% (n=21), A/V: 48% (n=29), and V/V: 17% (n=10). Twenty-four-hour energy expenditure, adjusted for fat-free mass, fat mass, and spontaneous physical activity, was 311 kJ/d lower (95% confidence interval: 24-598 kJ/d, P=0.03) in the V/V homozygotes than in the A/A and A/V genotypes. The V/V had approximately 20% higher 24-h spontaneous physical activity, particularly higher at night (P<0.005). Energy expenditure due to higher spontaneous physical activity counteracted the V/V group's lower 24-h resting energy expenditure for a given body size and composition. 24-h RQ adjusted for energy balance, age, sex and spontaneous physical activity, was higher in the V/V homozygotes than in the AA and A /V groups (P<0.05). CONCLUSIONS: Subjects with the V/V genotype of the UCP2 gene exhibit an enhanced metabolic efficiency and lower fat oxidation than the A/A and A/V genotypes.